A woman holds a picture of Venezuela's President Hugo Chavez as supporters gather at Simon Bolivar square in Caracas on Dec. 9, 2012. (Fernando Llano/AP)

Venezuelan President Hugo Chavez arrived in Cuba in the early morning hours Monday to undergo his fourth cancer surgery in 18 months, after dramatically designating a successor in case his illness forces him to leave office after nearly 14 years.

State television images showed Chavez hugging his close associates, including Vice President Nicolas Maduro, the man he says might replace him, before boarding a plane for Havana about 1 a.m.

“Long live the fatherland,” Chavez said.

One of his closest aides, Elias Jaua, later recounted in his Twitter feed how he had hugged Chavez. “I said, ‘Go and come back,’” Jaua wrote. “And he said, ‘Of course, I’ll be back, Elias.’ Amen!”

In his struggle with cancer, Chavez, 58, has returned from treatment in Cuba several times already. But his announcement Saturday that “some malignant cells” had been detected in his pelvic region that would necessitate surgery in Havana’s Cimeq hospital, where he has been treated before, and his instructions that Maduro had his confidence and should take over if necessary, were sober reminders that his illness is proving hard to beat.

“If something happens that sidelines me, which under the constitution requires a new presidential election, you should elect Nicolas Maduro as president,” Chavez said, sitting at a table with Maduro at his side. “I ask that of you from my heart.”

Moises Naim, a former Venezuelan government official who is an analyst at the Carnegie Endowment for International Peace in Washington, called the announcement “basically a farewell speech.”

“He said goodbye to power,” Naim said. “It’s a statement full of resignation and appeals to God. There is no plan. The only talk of the future is that there will be elections, and he asks for people to vote for Maduro.”

Chavez’s departure from office would mark the end of a tumultuous rule in which the leftist former army officer harnessed Venezuela’s considerable oil wealth to shower the poor with social programs while engineering a sharp diplomatic shift away from the country’s historical ally, the United States.

Chavez’s government forged alliances with some of Washington’s most intransigent adversaries, including Cuba, Iran and Syrian President Bashar al-Assad. He has used his lock on practically all levers of power, from the courts to the congress, to push forward the nationalization of hundreds of private companies and the seizure of wide swaths of farmland.

For Venezuela’s opposition, the possible scenarios that Chavez discussed in Saturday’s address amount to the first time the president has publicly acknowledged the severity of his illness and the impact it could have on the future of the country.

No one in the government is authorized to discuss Chavez’s medical condition except Chavez himself, who astonished his countrymen in June 2011 by telling them he had gone under the knife twice to remove a malignant growth. A third surgery followed in February.

Chavez has never disclosed what kind of cancer he has or where it is located. He has twice pronounced himself cured, without providing details.

“It was time to tell the truth to the country,” said Maria Corina Machado, an opposition member of the National Assembly. “Venezuela has been living with a lot of uncertainty. In a democratic country where the constitution is obeyed, the president must talk about his health when it is compromised.”

Should Chavez die or have to resign, the constitution calls for Venezuela to stage presidential elections within 30 days. Maduro, a 50-year-old former union organizer and bus driver who has risen through the ranks of Chavez’s movement, would become the candidate of the president’s United Socialist Party.

The constitution also requires that the vice president fill in for the president should he be temporarily absent. Chavez has spent many weeks in Cuba in the past 18 months, undergoing chemotherapy and radiation treatments. But he has remained in charge of the government, signing decrees and bills from Havana.

Machado said the opposition will call for a strict interpretation of the constitution now that Chavez has suggested the possibility of stepping aside.

“Article 233 of the constitution is clear about the only mechanism, an election within 30 days,” she said. “He can’t name a successor. It’s the Venezuelan people who decide.”

An election would mean a contest between Maduro and the opposition’s leader, Henrique Capriles.

Capriles lost to Chavez in the presidential election held Oct. 7, with the incumbent winning 55 percent of the vote to the challenger’s 44 percent. Polls, though, have shown that Capriles is more popular in Venezuela than all of Chavez’s closest associates, including Maduro.

The president’s swearing-in for another six-year term is scheduled for Jan. 10, but his announcement, following weeks in which he remained out of public view, raised questions about whether the inauguration will take place.

“This is how life goes,” Chavez said in his televised address, which prompted his followers to gather in churches and public squares to pray and chant slogans supporting him. “God willing, I hope to be able to give you good news in the coming days.”